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package com.sun.org.glassfish.external.statistics.impl;

import java.util.Map;
import java.lang.reflect.*;
import com.sun.org.glassfish.external.statistics.AverageRangeStatistic;

An implementation of AverageRangeStatistic that provides ways to change the
state externally through mutators.  Convenience class that is useful for
components that gather the statistical data.
By merely changing the count (which is a mandatory measurement), rest of the statistical
information could be deduced.
/**
 * An implementation of AverageRangeStatistic that provides ways to change the
 * state externally through mutators.  Convenience class that is useful for
 * components that gather the statistical data.
 * By merely changing the count (which is a mandatory measurement), rest of the statistical
 * information could be deduced.
 */

public final class AverageRangeStatisticImpl extends StatisticImpl implements
        AverageRangeStatistic, InvocationHandler {

    private long currentVal = 0L;
    private long highWaterMark = Long.MIN_VALUE;
    private long lowWaterMark = Long.MAX_VALUE;
    private long numberOfSamples = 0L;
    private long runningTotal = 0L;

    private final long initCurrentVal;
    private final long initHighWaterMark;
    private final long initLowWaterMark;
    private final long initNumberOfSamples;
    private final long initRunningTotal;

    private final AverageRangeStatistic as =
            (AverageRangeStatistic) Proxy.newProxyInstance(
            AverageRangeStatistic.class.getClassLoader(),
            new Class[] { AverageRangeStatistic.class },
            this);

    public AverageRangeStatisticImpl(long curVal, long highMark, long lowMark,
                                     String name, String unit, String desc,
                                     long startTime, long sampleTime) {
        super(name, unit, desc, startTime, sampleTime);
        currentVal = curVal;
        initCurrentVal = curVal;
        highWaterMark = highMark;
        initHighWaterMark = highMark;
        lowWaterMark = lowMark;
        initLowWaterMark = lowMark;
        numberOfSamples = 0L;
        initNumberOfSamples = numberOfSamples;
        runningTotal = 0L;
        initRunningTotal = runningTotal;
    }

    public synchronized AverageRangeStatistic getStatistic() {
        return as;
    }

    public synchronized String toString() {
        return super.toString() + NEWLINE +
            "Current: " + getCurrent() + NEWLINE +
            "LowWaterMark: " + getLowWaterMark() + NEWLINE +
            "HighWaterMark: " + getHighWaterMark() + NEWLINE +
            "Average:" + getAverage();
    }

    public synchronized Map getStaticAsMap() {
        Map m = super.getStaticAsMap();
        m.put("current", getCurrent());
        m.put("lowwatermark", getLowWaterMark());
        m.put("highwatermark", getHighWaterMark());
        m.put("average", getAverage());
        return m;
    }

    public synchronized void reset() {
        super.reset();
        currentVal = initCurrentVal;
        highWaterMark = initHighWaterMark;
        lowWaterMark = initLowWaterMark;
        numberOfSamples = initNumberOfSamples;
        runningTotal = initRunningTotal;
        sampleTime = -1L;
    }

    public synchronized long getAverage() {
        if(numberOfSamples == 0) {
            return -1;
        } else {
            return runningTotal / numberOfSamples;
        }
    }

    public synchronized long getCurrent() {
        return currentVal;
    }

    public synchronized void setCurrent(long curVal) {
        currentVal = curVal;
        lowWaterMark = (curVal >= lowWaterMark ? lowWaterMark : curVal);
        highWaterMark = (curVal >= highWaterMark ? curVal : highWaterMark);
        numberOfSamples++;
        runningTotal += curVal;
        sampleTime = System.currentTimeMillis();
    }

    public synchronized long getHighWaterMark() {
        return highWaterMark;
    }

    public synchronized long getLowWaterMark() {
        return lowWaterMark;
    }

    // todo: equals implementation
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        checkMethod(method);

        Object result;
        try {
            result = method.invoke(this, args);
        } catch (InvocationTargetException e) {
            throw e.getTargetException();
        } catch (Exception e) {
            throw new RuntimeException("unexpected invocation exception: " +
                       e.getMessage());
        }
        return result;
    }

}